Liquid/gas separators operating at atmospheric pressure, sometimes referred to as gas busters, are standard equipment on virtually all oil and gas rigs. Because gas busters operate at atmospheric pressure, they offer operational simplicity by not requiring control valves for the gas discharge line or the liquid discharge line. Pressurized liquid/gas separators are traditionally designed to operate with moderate backpressure, e.g., less than 50 psi. Pressurized separators are utilized to overcome line pressure losses when an extensive length of vent line is required to safely flare or vent hazardous gas at a specific distance from other operations for safety reasons. Pressurized separators may be used with high H2S content.
Standard gas busters utilize a U-tube on the liquid outlet line that creates a liquid hydraulic seal to prevent gaseous components from exiting the separator through the liquid outlet. The hydrostatic pressure created by the U-tube may determine the maximum allowable pressure under which a gas buster can operate.